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Citrus Weed Management- Efficacy, Longevity &
Crop-safety
Horticultural Sciences
Ramdas KanisserySouthwest Florida Res. & Education CenterImmokalee
Brent Sellers & Steve Futch
Citrus Weed Management
Managing difficult to control weeds
Research updates – steaming for weed mgmt. in citrus
Impacts of herbicides on citrus yield & productivity
PRE-emergent herbicide trials for long-term weed control
Efficacy
Longevity
Crop-safety
Citrus Weed Management
Research updates – steaming for weed mgmt. in citrus
Impacts of herbicides on citrus yield & productivity
PRE-emergent herbicide trials for long-term weed control
Efficacy
Longevity
Managing difficult to control weeds
Crop-safety
Weed management in citrus groves
Weed managed citrus rows
- ‘Weed free’ rows or under trees
Weed management in citrus groves
Weeds come up quickly in the citrus rows
- Constant supply of moisture from tree irrigation
- Major challenge is ‘longer-term’ suppression of weeds
Important strategy to prevent weed outbreak in your grove
“NEVER LET ‘EM SET SEED”
Heavy infestation of tropical whiteweed in citrus tree rows
Heavy infestation of tropical whiteweed in citrus tree rows
Heavy infestation of “tropical whiteweed” in citrus tree rows
10
Clustered pellitoryinfestation
11
Clustered pellitoryinfestation
Seed bank formed in the soil
Managed by broad-spectrum POST-emergent sprays- glyphosate- paraquat
Goat weed
- Slow response to glyphosate & paraquat application
Goat weed
- Slow response to glyphosate & paraquat application
- Tiny seeds released from the ‘seed pods’
- Each plant can potentially add hundreds of thousands of seeds to soil
- Monoculture of goatweed
Heavy seed setters
Amaranth / Pigweed
Black Nightshade
Parthenium
- Each plant can potentially add hundreds of thousands of seeds to soil
• Active ingredient – Brand name(s)
POSTFoliar applied
•PR
E-EMER
GEN
TH
ERBIC
IDES
Selective herbicides
• Saflufenacil – Treevix
Consult Florida Citrus Production Guide 2018-19 for a complete list
• Carfentrazone – Aim EC
• Glyphosate + 2,4-D - Landmaster
• Paraquat - Gramoxone
• Active ingredient – Brand name(s)
POSTFoliar applied
Consult Florida Citrus Production Guide 2018-19 for a complete list
Non-selective herbicides
• Carfentrazone – Aim EC
• Glyphosate + 2,4-D - Landmaster
• Paraquat - Gramoxone
• Active ingredient – Brand name(s)
POSTFoliar applied
Consult Florida Citrus Production Guide 2018-19 for a complete list
Non-selective herbicides
• Glufosinate ammonium - Rely 280
Heavy seed setters
Amaranth / Pigweed
Black Nightshade
Parthenium
Glufosinate is an effective management option for parthenium
POSTFoliar applied
•PR
E-EMER
GEN
TH
ERBIC
IDES
Spray coverage on foliage – key factor
Higher spray volumes 20 to 30 gallons per acre
- Dense weed infestations- Large weeds / advanced growth
stage
POSTFoliar applied
•PR
E-EMER
GEN
TH
ERBIC
IDES
Spray coverage on foliage – key factor
Higher spray volumes 20 to 30 gallons per acre
- Dense weed infestations- Large weeds / advanced growth
stage
Surfactant addition
Citrus Weed Management
Research updates – steaming for weed mgmt. in citrus
Impacts of herbicides on citrus yield & productivity
PRE-emergent herbicide trials for long-term weed control
Efficacy
Longevity
Managing difficult to control weeds
Crop-safety
Applied to bare soil or minimum ‘existent weed coverage’ to ensure max soil incorporation
Pre-emergent OR Residual
herbicides Prevent seed germination
Active Ingredient(s) Products
Flumioxazin Chateau
Indaziflam Alion
Pre-emergent OR Residual
herbicides
Consult Florida Citrus Production Guide 2018-19 for a complete list
Active Ingredient(s) Products Product Rate
(per acre)
Flumioxazin Chateau 6 oz.
Flumioxazin Chateau 8 oz.
Indaziflam Alion 3 oz.
Indaziflam Alion 5 oz.
Flumioxazin +Indaziflam
Chateau +Alion 6 oz. + 3 oz.
Flumioxazin +Indaziflam
Chateau +Alion 8 oz. + 5 oz.
Control -- --
Study location: Immokalee
Active Ingredient(s) Products Product Rate
(per acre)
Flumioxazin Chateau 6 oz.
Flumioxazin Chateau 8 oz.
Indaziflam Alion 3 oz.
Indaziflam Alion 5 oz.
Flumioxazin +Indaziflam
Chateau +Alion 6 oz. + 3 oz.
Flumioxazin +Indaziflam
Chateau +Alion 8 oz. + 5 oz.
Control -- --
Study location: Immokalee
Study location: Immokalee
Active Ingredient(s) Products Product Rate
(per acre)
Flumioxazin Chateau 6 oz.
Flumioxazin Chateau 8 oz.
Indaziflam Alion 3 oz.
Indaziflam Alion 5 oz.
Flumioxazin +Indaziflam
Chateau +Alion 6 oz. + 3 oz.
Flumioxazin +Indaziflam
Chateau +Alion 8 oz. + 5 oz.
Control -- --
2 MonthsWeed control efficacy (%)
- Replication (n) = 5- Mean comparison: Tukey’s hsd (a 0.05)- All treatments including control received
glyphosate at ~2.0 lbs. A.E/acre
75%
Study location: Immokalee
Active Ingredient(s) Products Product Rate
(per acre)
Flumioxazin Chateau 6 oz.
Flumioxazin Chateau 8 oz.
Indaziflam Alion 3 oz.
Indaziflam Alion 5 oz.
Flumioxazin +Indaziflam
Chateau +Alion 6 oz. + 3 oz.
Flumioxazin +Indaziflam
Chateau +Alion 8 oz. + 5 oz.
Control -- --
Weed control efficacy (%)
5+ Months
75%
- Replication (n) = 5- Mean comparison: Tukey’s hsd (a 0.05)- All treatments including control received
glyphosate at ~2.0 lbs. A.E/acre
Study location: Immokalee
2 Months 2 Months
5 months after applicationIndaziflam + Flumioxazin
Study location: Immokalee
Active Ingredient(s) Products Product Rate
(per acre)
Flumioxazin Chateau 6 oz.
Flumioxazin Chateau 8 oz.
Indaziflam Alion 3 oz.
Indaziflam Alion 5 oz.
Flumioxazin +Indaziflam
Chateau +Alion 6 oz. + 3 oz.
Flumioxazin +Indaziflam
Chateau +Alion 8 oz. + 5 oz.
Control -- -- Study location: Zolfo springs
Active Ingredient(s) Products Product Rate
(per acre)
Flumioxazin Chateau 6 oz.
Flumioxazin Chateau 8 oz.
Indaziflam Alion 3 oz.
Indaziflam Alion 5 oz.
Flumioxazin +Indaziflam
Chateau +Alion 6 oz. + 3 oz.
Flumioxazin +Indaziflam
Chateau +Alion 8 oz. + 5 oz.
Control -- --
2 MonthsWeed control efficacy (%)
75%
- Replication (n) = 5
Study location: Zolfo springs
Active Ingredient(s) Products Product Rate
(per acre)
Flumioxazin Chateau 6 oz.
Flumioxazin Chateau 8 oz.
Indaziflam Alion 3 oz.
Indaziflam Alion 5 oz.
Flumioxazin +Indaziflam
Chateau +Alion 6 oz. + 3 oz.
Flumioxazin +Indaziflam
Chateau +Alion 8 oz. + 5 oz.
Control -- --
∼5 MonthsWeed control efficacy (%)
75%
- Replication (n) = 5
Study location: Zolfo springs
Citrus Weed Management
Research updates – steaming for weed mgmt. in citrus
Impacts of herbicides on citrus yield & productivity
PRE-emergent herbicide trials for long-term weed control
Efficacy
Longevity
Managing difficult to control weeds
Crop-safety
-Glyphosate application
Impacts of herbicides on citrus health and yield
- most popular post-emergent herbicide in citrus
- glyphosate reliant weed mgmt. programs (3-4 applications / yr)
-Glyphosate application
Spray contact
Impacts of herbicides on citrus health and yield
38
Credits: Steve Futch
Citrus drop from glyphosate spray contact with fruit
-Glyphosate application
Persistence in soil Citrus uptake
Glyphosate residues
Degradation products
Impacts of herbicides on citrus health and yield
Spray contact
Impacts of herbicides on citrus health and yield
- To investigate glyphosate linked fruit drop in citrus
Treatment Rate(a.e / A) Product
Control – water spray -- --
Low 0.75 22 oz/A
Medium 1.50 44 oz/A
High 3.75 110 oz/A
glyphosate rates
Impacts of herbicides on citrus health and yield
- To investigate glyphosate linked fruit drop in citrus
- Application was made during Nov – Feb
- Valencia
Impacts of herbicides on citrus health and yield
Fruit Detachment Force (FDF) – indicator of fruit holding capacity
- To investigate glyphosate linked fruit drop in citrus
FDF = higher possibility of fruit drop
- Application was made during Nov – Feb
- Valencia
FDF = higher possibility of fruit drop
FDF response to glyphosate rates
Kanissery, Batuman & Alferez (2018)
3
5
7
9
0 1 2 3 4 5 6 7 8
Frui
t det
achm
ent f
orce
(FD
F)
Weeks after glyphosate application
Control Low Medium High
2017 study
- Replication (n) = 100
FDF = higher possibility of fruit drop
FDF response to glyphosate rates
Kanissery, Batuman & Alferez (2018)
3
5
7
9
0 1 2 3 4 5 6 7 8
Frui
t det
achm
ent f
orce
(FD
F)
Weeks after glyphosate application
Control Low Medium High
2017 study
- Replication (n) = 100
FDF = higher possibility of fruit drop
FDF response to glyphosate rates
Kanissery, Batuman & Alferez (2018)
3
5
7
9
0 1 2 3 4 5 6 7
Frui
t det
achm
ent f
orce
(FD
F)
Weeks after glyphosate application
Control Low Medium High
2018 study
- Replication (n) = 100
16.53% 15.94%
13.36%15.42%
0
5
10
15
20
Control Low Medium High
FRU
IT D
ROP
(% O
F IN
ITIA
L FR
UIT
SET
)
HERBICIDE TEST RATES
2018 study
Citrus fruit drop v/s glyphosate application
% of fruit dropped - No statistical difference b/w treatments observed in this study
Yield was low in the control- Competition from
weeds
- Replication (n) = 20
-Glyphosate application
Persistence in soil Citrus uptake
Glyphosate residues
Degradation products
Impacts of herbicides on citrus health and yield
-Glyphosate in citrus production
Persistence in soil (?) Citrus uptake
Glyphosate residues
Degradation products
Impacts of herbicides on citrus health and yield
Fruit drop / Yield
Root growth (?)
CollaboratorsDr. Batuman(PATH)Dr. Kadyampakeni(SWS)Dr. Dittmar(HOS)Dr. Alferez(HOS)
Citrus Weed Management
Research update – steaming for weed mgmt. in citrus
Impacts of herbicides on citrus yield & productivity
PRE-emergent herbicide trials for long-term weed control
Efficacy
Longevity
Managing difficult to control weeds
Crop-safety
Steaming – in citrus weed management
- Non-chemical weed management
- Sustainable
Mobile boom connected to steamer
Steam generator
Collaborator(s)Dr. Ampatzidis (ABE)Dr. Abdulridha
Steaming – in citrus weed management
Steamer pulled by tractor
- Non-chemical weed management
- Sustainable
Steaming – in citrus weed management
- For weed management in the citrus rows
Steam application for citrus row weed control
Collaborator(s)Dr. Ampatzidis (ABE)Dr. Abdulridha
Steaming – in citrus weed management
- For weed management in the citrus rows
∼ 6 hrs. after steam application
Steam application for citrus row weed control
Steaming – in citrus weed management
- For weed management in the citrus rows
Untreated Control
Steam applied
Goat weed control in citrus
- Steam was applied followed by a contact herbicide
Steaming in combination with herbicide application
No steam
With Steam
Paraquat rate (pt. / acre)
Goat weed control in citrus
- Steam was applied followed by a contact herbicide
Steaming in combination with herbicide application
No steam
With Steam
Paraquat rate (pt. / acre)
0
1
3
No steam
With Steam
Paraquat rate (pt. / acre)
0 0c 50c
1 46b 89a
3 93a 96a
CV 17.37
P-value 0.0013
1 Day after treatmentGoat weed control in citrus
- Steam was applied followed by a contact herbicide
- Contact herbicide found effective even at lower application rate when combined with steam application
- Replication (n) = 5- Mean comparison: Tukey’s hsd (α 0.05)
% weed control
Steaming in combination with herbicide application
No steam
With Steam
Paraquat rate (pt. / acre)
0 0c 54b
1 51b 92a
3 95a 96a
CV 19.64
P-value 0.0021
8 Days after treatment
% weed control
Goat weed control in citrus
- Steam was applied followed by a contact herbicide
- Contact herbicide found effective even at lower application rate when combined with steam application
- Replication (n) = 5- Mean comparison: Tukey’s hsd (α 0.05)
Steaming in combination with herbicide application
Collaborator(s)Dr. Ampatzidis (ABE)Dr. Abdulridha
59
Summary
Difficult to control weeds- POST sprays before flowering/seeding- Coverage - Spray volume ; surfactants
Summary: Citrus weed management
PRE-herbicide combinations- Longer term weed control- Dealing with large data sets
Effects of glyphosate on fruit drop / yield- Could potentially lower the FDF- No significant %fruit drop observed
Steaming for weed management- Steaming + herbicide- Efficacy at low rates of chemicals
SWFREC weed science team
From left: Shea Teems, Biwek Gairhe, Robert Riefer, Ramdas KanisseryIn set: Cami McAvoy, Maria Martinez, Budji Toussaint
Thank you…
Contact
Ramdas Kanissery
UF/IFAS SWFREC2685 State Road NImmokalee, FL
Phone: (239) [email protected]
61